I was going crazy with the same problem - i wiped my whole system and reinstalled windows, and STILL HAD this problem. Everytime i started a game my sound would LOOP and im stuck at NS screen.
I tried every friggen Nvidia driver there was, then cause it was a gigabyte nvidia card i tried the manufacturers drivers too, NOTHING WORKED except now i could get into game but now everything is DARKK !!!
Then i played with gamma tweaks in console, nothing helped. Somthing was not good at all and now i had dark gamma with stange colours everywhere.
The one where scoresheets are coloured in green instead of the normal yellow and blue. Another thing is that the icons next to peoples names are silhouetted to just black, with no colour. Some textures in game will be black, even hives, and lots of other wierd stuff, my fps would be down too.
and the most annoying thing, EVERYTHING is just DARKK, no gamma ramp settings didnt do ######.
GUESS what it WAS !!!!
WinVNC <------------- my version was called " Ultra VNC "
I love this program but dammmmmmmmmmm, it screws my NS
i simply DISABLED it in Device Manager (it makes a virtual video card) and started a game.
Instantly NS GAMMA went back BRIGHT !! AGAIN AND MAX FPS
All in All, wasted 2 months of my life, hope this helps cause i found SOOOOOOO many people with this problem and no one has cracked it yet.

YeeeeeaaaahhhhhhhHHHHHHHHH !!!!!!
Peace Out.